These teachings relate generally to chromic luminescent compositions, and more particularly, to the preparation and use of combinations of luminescent and non-luminescent materials that are capable of modulating color and brightness as a function of incident electromagnetic radiation and further can also be tailored to enable changes in color or brightness pattern frequency.
Currently, the majority of color renditions are achieved by deploying absorptive-only non-luminescent compositions. Although such absorptive-only non-luminescent compositions can achieve a wide color gamut, these compositions are static, that is, once applied they remain the same and hence cannot change color as the incident electromagnetic radiation changes. Furthermore as incident electromagnetic radiation intensity changes, such compositions also do not enable variations in brightness or additionally, the frequency of a pattern. As a result, the use of these compositions is substantially limiting.
There is, therefore, a need for utilizing combinations of non-luminescent and luminescent materials rendered as chromic luminescent compositions which are capable of modulating color and brightness as incident electromagnetic radiation intensity changes for a variety of applications. It is also desirable to provide for combinations of non-luminescent and luminescent materials rendered as chromic luminescent compositions that have the ability, where applicable, to alter the frequency of a color or brightness pattern as incident electromagnetic radiation intensity changes. Thus, there is a need for chromic luminescent compositions that employ both absorptive properties and emissive properties so as to achieve the ability to vary color and brightness and optionally, frequency.
Chromic luminescent compositions that, as a function of incident radiation, modulate color and brightness, as well as frequency of a pattern if desired, can have substantial utility in a number of different areas, such as for aesthetic purposes or commercial appeal. There is a need for compositions that enable changes in color and brightness to provide decorative and/or fashion effects that are not possible with the use of today's static compositions. Furthermore, these chromic luminescent compositions have significant use in camouflage systems.
Today's camouflage systems are sophisticated combinations of colored macro and/or micro patterns, as described in U.S. Pat. No. 6,805,957, that are developed to address disruption of shape and background matching for the purpose of concealment. These systems generally use absorptive pigments that subtract a certain fraction of incident radiation to produce a desired reflectance value rendered as a repeat pattern so as to achieve a brightness level similar to that of the selected surrounding for which concealment is warranted. Ideally, movement from a high frequency domain, such as a woodland terrain, to a low frequency domain, such as flat terrain, should be accompanied by a diminished pattern and increased brightness in order to minimize contrast with the background. However, this does not occur with the current camouflage systems since, once applied, they produce a reflectance value and pattern frequency that are static, i.e. they will not change as the environment and/or terrain changes, and are therefore unlikely to be as effective throughout the 24 hr day/night cycle, as well as where different terrains are encountered. It can be appreciated that when the environment is darker the color should become less bright to better blend in with the surroundings and conversely, for very bright surroundings, the colors should be brighter.
Furthermore, although there have been attempts at adaptive camouflage systems that utilize various triggers, such as those cited in U.S. Pat. No. 5,985,381 and U.S. Pat. No. 5,144,877, the technologies described in these patents rely on the varying absorptive properties of dyes formed via molecular rearrangements following either sunlight exposure or temperature change to affect color change, i.e. they are going from a colorless or light colored state to a darker colored state. The teachings in these patents are to provide an additive color function on top of the base static camouflage colors and as a result, do not then have the ability to modulate brightness so as to minimize contrast.
The human eye contains two types of photoreceptors, rods and cones. The rods are more numerous, some 120 million, and perceive brightness. The cones, of which there are 6 to 7 million, provide the eye's sensitivity to color. As a consequence, given the significantly larger number of receptors that detect variations in brightness, minimizing detection for any adaptive camouflage scheme should encompass the ability to vary at least brightness in addition to color. Unfortunately, today's camouflage systems are static and do not provide a mechanism to account for varying color and brightness, as well as frequency if applicable, so as to more effectively reduce contrast as local environment and/or terrain changes, and therefore are unable to provide optimum concealment.
Given the existing camouflage systems, there is a further need for these chromic luminescent compositions to be utilized in camouflage systems in order to produce a system that is not static, that changes as a function of incident electromagnetic radiation intensity resulting from the environment or terrain, that provides the ability to modulate color and brightness, and as required to additionally modulate frequency. This will result in a more efficient camouflage system over that of the current camouflage systems, based on having the ability to continuously adapt to the incident electromagnetic radiation intensity relative to the surrounding environment and/or terrain.